2 * QEMU Block driver for DMG images
4 * Copyright (c) 2004 Johannes E. Schindelin
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 #include "qemu/osdep.h"
25 #include "qapi/error.h"
26 #include "qemu-common.h"
27 #include "block/block_int.h"
28 #include "qemu/bswap.h"
29 #include "qemu/error-report.h"
30 #include "qemu/module.h"
33 int (*dmg_uncompress_bz2
)(char *next_in
, unsigned int avail_in
,
34 char *next_out
, unsigned int avail_out
);
36 int (*dmg_uncompress_lzfse
)(char *next_in
, unsigned int avail_in
,
37 char *next_out
, unsigned int avail_out
);
40 /* Limit chunk sizes to prevent unreasonable amounts of memory being used
41 * or truncating when converting to 32-bit types
43 DMG_LENGTHS_MAX
= 64 * 1024 * 1024, /* 64 MB */
44 DMG_SECTORCOUNTS_MAX
= DMG_LENGTHS_MAX
/ 512,
49 UDZE
= 0, /* Zeroes */
56 UDCM
= 0x7ffffffe, /* Comments */
60 static int dmg_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
68 len
= strlen(filename
);
69 if (len
> 4 && !strcmp(filename
+ len
- 4, ".dmg")) {
75 static int read_uint64(BlockDriverState
*bs
, int64_t offset
, uint64_t *result
)
80 ret
= bdrv_pread(bs
->file
, offset
, &buffer
, 8);
85 *result
= be64_to_cpu(buffer
);
89 static int read_uint32(BlockDriverState
*bs
, int64_t offset
, uint32_t *result
)
94 ret
= bdrv_pread(bs
->file
, offset
, &buffer
, 4);
99 *result
= be32_to_cpu(buffer
);
103 static inline uint64_t buff_read_uint64(const uint8_t *buffer
, int64_t offset
)
105 return be64_to_cpu(*(uint64_t *)&buffer
[offset
]);
108 static inline uint32_t buff_read_uint32(const uint8_t *buffer
, int64_t offset
)
110 return be32_to_cpu(*(uint32_t *)&buffer
[offset
]);
113 /* Increase max chunk sizes, if necessary. This function is used to calculate
114 * the buffer sizes needed for compressed/uncompressed chunk I/O.
116 static void update_max_chunk_size(BDRVDMGState
*s
, uint32_t chunk
,
117 uint32_t *max_compressed_size
,
118 uint32_t *max_sectors_per_chunk
)
120 uint32_t compressed_size
= 0;
121 uint32_t uncompressed_sectors
= 0;
123 switch (s
->types
[chunk
]) {
124 case UDZO
: /* zlib compressed */
125 case UDBZ
: /* bzip2 compressed */
126 case ULFO
: /* lzfse compressed */
127 compressed_size
= s
->lengths
[chunk
];
128 uncompressed_sectors
= s
->sectorcounts
[chunk
];
130 case UDRW
: /* copy */
131 uncompressed_sectors
= DIV_ROUND_UP(s
->lengths
[chunk
], 512);
133 case UDIG
: /* zero */
134 /* as the all-zeroes block may be large, it is treated specially: the
135 * sector is not copied from a large buffer, a simple memset is used
136 * instead. Therefore uncompressed_sectors does not need to be set. */
140 if (compressed_size
> *max_compressed_size
) {
141 *max_compressed_size
= compressed_size
;
143 if (uncompressed_sectors
> *max_sectors_per_chunk
) {
144 *max_sectors_per_chunk
= uncompressed_sectors
;
148 static int64_t dmg_find_koly_offset(BdrvChild
*file
, Error
**errp
)
150 BlockDriverState
*file_bs
= file
->bs
;
156 /* bdrv_getlength returns a multiple of block size (512), rounded up. Since
157 * dmg images can have odd sizes, try to look for the "koly" magic which
158 * marks the begin of the UDIF trailer (512 bytes). This magic can be found
159 * in the last 511 bytes of the second-last sector or the first 4 bytes of
160 * the last sector (search space: 515 bytes) */
161 length
= bdrv_getlength(file_bs
);
163 error_setg_errno(errp
, -length
,
164 "Failed to get file size while reading UDIF trailer");
166 } else if (length
< 512) {
167 error_setg(errp
, "dmg file must be at least 512 bytes long");
170 if (length
> 511 + 512) {
171 offset
= length
- 511 - 512;
173 length
= length
< 515 ? length
: 515;
174 ret
= bdrv_pread(file
, offset
, buffer
, length
);
176 error_setg_errno(errp
, -ret
, "Failed while reading UDIF trailer");
179 for (i
= 0; i
< length
- 3; i
++) {
180 if (buffer
[i
] == 'k' && buffer
[i
+1] == 'o' &&
181 buffer
[i
+2] == 'l' && buffer
[i
+3] == 'y') {
185 error_setg(errp
, "Could not locate UDIF trailer in dmg file");
189 /* used when building the sector table */
190 typedef struct DmgHeaderState
{
191 /* used internally by dmg_read_mish_block to remember offsets of blocks
193 uint64_t data_fork_offset
;
194 /* exported for dmg_open */
195 uint32_t max_compressed_size
;
196 uint32_t max_sectors_per_chunk
;
199 static bool dmg_is_known_block_type(uint32_t entry_type
)
201 switch (entry_type
) {
202 case UDRW
: /* uncompressed */
203 case UDIG
: /* zeroes */
204 case UDZO
: /* zlib */
206 case UDBZ
: /* bzip2 */
207 return !!dmg_uncompress_bz2
;
208 case ULFO
: /* lzfse */
209 return !!dmg_uncompress_lzfse
;
215 static int dmg_read_mish_block(BDRVDMGState
*s
, DmgHeaderState
*ds
,
216 uint8_t *buffer
, uint32_t count
)
221 uint32_t chunk_count
;
223 uint64_t data_offset
;
224 uint64_t in_offset
= ds
->data_fork_offset
;
227 type
= buff_read_uint32(buffer
, offset
);
228 /* skip data that is not a valid MISH block (invalid magic or too small) */
229 if (type
!= 0x6d697368 || count
< 244) {
230 /* assume success for now */
234 /* chunk offsets are relative to this sector number */
235 out_offset
= buff_read_uint64(buffer
, offset
+ 8);
237 /* location in data fork for (compressed) blob (in bytes) */
238 data_offset
= buff_read_uint64(buffer
, offset
+ 0x18);
239 in_offset
+= data_offset
;
241 /* move to begin of chunk entries */
244 chunk_count
= (count
- 204) / 40;
245 new_size
= sizeof(uint64_t) * (s
->n_chunks
+ chunk_count
);
246 s
->types
= g_realloc(s
->types
, new_size
/ 2);
247 s
->offsets
= g_realloc(s
->offsets
, new_size
);
248 s
->lengths
= g_realloc(s
->lengths
, new_size
);
249 s
->sectors
= g_realloc(s
->sectors
, new_size
);
250 s
->sectorcounts
= g_realloc(s
->sectorcounts
, new_size
);
252 for (i
= s
->n_chunks
; i
< s
->n_chunks
+ chunk_count
; i
++) {
253 s
->types
[i
] = buff_read_uint32(buffer
, offset
);
254 if (!dmg_is_known_block_type(s
->types
[i
])) {
262 s
->sectors
[i
] = buff_read_uint64(buffer
, offset
+ 8);
263 s
->sectors
[i
] += out_offset
;
266 s
->sectorcounts
[i
] = buff_read_uint64(buffer
, offset
+ 0x10);
268 /* all-zeroes sector (type 2) does not need to be "uncompressed" and can
269 * therefore be unbounded. */
270 if (s
->types
[i
] != 2 && s
->sectorcounts
[i
] > DMG_SECTORCOUNTS_MAX
) {
271 error_report("sector count %" PRIu64
" for chunk %" PRIu32
272 " is larger than max (%u)",
273 s
->sectorcounts
[i
], i
, DMG_SECTORCOUNTS_MAX
);
278 /* offset in (compressed) data fork */
279 s
->offsets
[i
] = buff_read_uint64(buffer
, offset
+ 0x18);
280 s
->offsets
[i
] += in_offset
;
282 /* length in (compressed) data fork */
283 s
->lengths
[i
] = buff_read_uint64(buffer
, offset
+ 0x20);
285 if (s
->lengths
[i
] > DMG_LENGTHS_MAX
) {
286 error_report("length %" PRIu64
" for chunk %" PRIu32
287 " is larger than max (%u)",
288 s
->lengths
[i
], i
, DMG_LENGTHS_MAX
);
293 update_max_chunk_size(s
, i
, &ds
->max_compressed_size
,
294 &ds
->max_sectors_per_chunk
);
297 s
->n_chunks
+= chunk_count
;
304 static int dmg_read_resource_fork(BlockDriverState
*bs
, DmgHeaderState
*ds
,
305 uint64_t info_begin
, uint64_t info_length
)
307 BDRVDMGState
*s
= bs
->opaque
;
309 uint32_t count
, rsrc_data_offset
;
310 uint8_t *buffer
= NULL
;
314 /* read offset from begin of resource fork (info_begin) to resource data */
315 ret
= read_uint32(bs
, info_begin
, &rsrc_data_offset
);
318 } else if (rsrc_data_offset
> info_length
) {
323 /* read length of resource data */
324 ret
= read_uint32(bs
, info_begin
+ 8, &count
);
327 } else if (count
== 0 || rsrc_data_offset
+ count
> info_length
) {
332 /* begin of resource data (consisting of one or more resources) */
333 offset
= info_begin
+ rsrc_data_offset
;
335 /* end of resource data (there is possibly a following resource map
336 * which will be ignored). */
337 info_end
= offset
+ count
;
339 /* read offsets (mish blocks) from one or more resources in resource data */
340 while (offset
< info_end
) {
341 /* size of following resource */
342 ret
= read_uint32(bs
, offset
, &count
);
345 } else if (count
== 0 || count
> info_end
- offset
) {
351 buffer
= g_realloc(buffer
, count
);
352 ret
= bdrv_pread(bs
->file
, offset
, buffer
, count
);
357 ret
= dmg_read_mish_block(s
, ds
, buffer
, count
);
361 /* advance offset by size of resource */
371 static int dmg_read_plist_xml(BlockDriverState
*bs
, DmgHeaderState
*ds
,
372 uint64_t info_begin
, uint64_t info_length
)
374 BDRVDMGState
*s
= bs
->opaque
;
376 uint8_t *buffer
= NULL
;
377 char *data_begin
, *data_end
;
379 /* Have at least some length to avoid NULL for g_malloc. Attempt to set a
380 * safe upper cap on the data length. A test sample had a XML length of
382 if (info_length
== 0 || info_length
> 16 * 1024 * 1024) {
387 buffer
= g_malloc(info_length
+ 1);
388 buffer
[info_length
] = '\0';
389 ret
= bdrv_pread(bs
->file
, info_begin
, buffer
, info_length
);
390 if (ret
!= info_length
) {
395 /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64
396 * decode. The actual data element has 431 (0x1af) bytes which includes tabs
398 data_end
= (char *)buffer
;
399 while ((data_begin
= strstr(data_end
, "<data>")) != NULL
) {
404 data_end
= strstr(data_begin
, "</data>");
406 if (data_end
== NULL
) {
411 mish
= g_base64_decode(data_begin
, &out_len
);
412 ret
= dmg_read_mish_block(s
, ds
, mish
, (uint32_t)out_len
);
425 static int dmg_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
428 BDRVDMGState
*s
= bs
->opaque
;
430 uint64_t rsrc_fork_offset
, rsrc_fork_length
;
431 uint64_t plist_xml_offset
, plist_xml_length
;
435 ret
= bdrv_apply_auto_read_only(bs
, NULL
, errp
);
440 bs
->file
= bdrv_open_child(NULL
, options
, "file", bs
, &child_file
,
446 block_module_load_one("dmg-bz2");
447 block_module_load_one("dmg-lzfse");
450 s
->offsets
= s
->lengths
= s
->sectors
= s
->sectorcounts
= NULL
;
451 /* used by dmg_read_mish_block to keep track of the current I/O position */
452 ds
.data_fork_offset
= 0;
453 ds
.max_compressed_size
= 1;
454 ds
.max_sectors_per_chunk
= 1;
456 /* locate the UDIF trailer */
457 offset
= dmg_find_koly_offset(bs
->file
, errp
);
463 /* offset of data fork (DataForkOffset) */
464 ret
= read_uint64(bs
, offset
+ 0x18, &ds
.data_fork_offset
);
467 } else if (ds
.data_fork_offset
> offset
) {
472 /* offset of resource fork (RsrcForkOffset) */
473 ret
= read_uint64(bs
, offset
+ 0x28, &rsrc_fork_offset
);
477 ret
= read_uint64(bs
, offset
+ 0x30, &rsrc_fork_length
);
481 if (rsrc_fork_offset
>= offset
||
482 rsrc_fork_length
> offset
- rsrc_fork_offset
) {
486 /* offset of property list (XMLOffset) */
487 ret
= read_uint64(bs
, offset
+ 0xd8, &plist_xml_offset
);
491 ret
= read_uint64(bs
, offset
+ 0xe0, &plist_xml_length
);
495 if (plist_xml_offset
>= offset
||
496 plist_xml_length
> offset
- plist_xml_offset
) {
500 ret
= read_uint64(bs
, offset
+ 0x1ec, (uint64_t *)&bs
->total_sectors
);
504 if (bs
->total_sectors
< 0) {
508 if (rsrc_fork_length
!= 0) {
509 ret
= dmg_read_resource_fork(bs
, &ds
,
510 rsrc_fork_offset
, rsrc_fork_length
);
514 } else if (plist_xml_length
!= 0) {
515 ret
= dmg_read_plist_xml(bs
, &ds
, plist_xml_offset
, plist_xml_length
);
524 /* initialize zlib engine */
525 s
->compressed_chunk
= qemu_try_blockalign(bs
->file
->bs
,
526 ds
.max_compressed_size
+ 1);
527 s
->uncompressed_chunk
= qemu_try_blockalign(bs
->file
->bs
,
528 512 * ds
.max_sectors_per_chunk
);
529 if (s
->compressed_chunk
== NULL
|| s
->uncompressed_chunk
== NULL
) {
534 if (inflateInit(&s
->zstream
) != Z_OK
) {
539 s
->current_chunk
= s
->n_chunks
;
541 qemu_co_mutex_init(&s
->lock
);
549 g_free(s
->sectorcounts
);
550 qemu_vfree(s
->compressed_chunk
);
551 qemu_vfree(s
->uncompressed_chunk
);
555 static void dmg_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
557 bs
->bl
.request_alignment
= BDRV_SECTOR_SIZE
; /* No sub-sector I/O */
560 static inline int is_sector_in_chunk(BDRVDMGState
* s
,
561 uint32_t chunk_num
, uint64_t sector_num
)
563 if (chunk_num
>= s
->n_chunks
|| s
->sectors
[chunk_num
] > sector_num
||
564 s
->sectors
[chunk_num
] + s
->sectorcounts
[chunk_num
] <= sector_num
) {
571 static inline uint32_t search_chunk(BDRVDMGState
*s
, uint64_t sector_num
)
574 uint32_t chunk1
= 0, chunk2
= s
->n_chunks
, chunk3
;
575 while (chunk1
!= chunk2
) {
576 chunk3
= (chunk1
+ chunk2
) / 2;
577 if (s
->sectors
[chunk3
] > sector_num
) {
579 } else if (s
->sectors
[chunk3
] + s
->sectorcounts
[chunk3
] > sector_num
) {
585 return s
->n_chunks
; /* error */
588 static inline int dmg_read_chunk(BlockDriverState
*bs
, uint64_t sector_num
)
590 BDRVDMGState
*s
= bs
->opaque
;
592 if (!is_sector_in_chunk(s
, s
->current_chunk
, sector_num
)) {
594 uint32_t chunk
= search_chunk(s
, sector_num
);
596 if (chunk
>= s
->n_chunks
) {
600 s
->current_chunk
= s
->n_chunks
;
601 switch (s
->types
[chunk
]) { /* block entry type */
602 case UDZO
: { /* zlib compressed */
603 /* we need to buffer, because only the chunk as whole can be
605 ret
= bdrv_pread(bs
->file
, s
->offsets
[chunk
],
606 s
->compressed_chunk
, s
->lengths
[chunk
]);
607 if (ret
!= s
->lengths
[chunk
]) {
611 s
->zstream
.next_in
= s
->compressed_chunk
;
612 s
->zstream
.avail_in
= s
->lengths
[chunk
];
613 s
->zstream
.next_out
= s
->uncompressed_chunk
;
614 s
->zstream
.avail_out
= 512 * s
->sectorcounts
[chunk
];
615 ret
= inflateReset(&s
->zstream
);
619 ret
= inflate(&s
->zstream
, Z_FINISH
);
620 if (ret
!= Z_STREAM_END
||
621 s
->zstream
.total_out
!= 512 * s
->sectorcounts
[chunk
]) {
625 case UDBZ
: /* bzip2 compressed */
626 if (!dmg_uncompress_bz2
) {
629 /* we need to buffer, because only the chunk as whole can be
631 ret
= bdrv_pread(bs
->file
, s
->offsets
[chunk
],
632 s
->compressed_chunk
, s
->lengths
[chunk
]);
633 if (ret
!= s
->lengths
[chunk
]) {
637 ret
= dmg_uncompress_bz2((char *)s
->compressed_chunk
,
638 (unsigned int) s
->lengths
[chunk
],
639 (char *)s
->uncompressed_chunk
,
641 (512 * s
->sectorcounts
[chunk
]));
647 if (!dmg_uncompress_lzfse
) {
650 /* we need to buffer, because only the chunk as whole can be
652 ret
= bdrv_pread(bs
->file
, s
->offsets
[chunk
],
653 s
->compressed_chunk
, s
->lengths
[chunk
]);
654 if (ret
!= s
->lengths
[chunk
]) {
658 ret
= dmg_uncompress_lzfse((char *)s
->compressed_chunk
,
659 (unsigned int) s
->lengths
[chunk
],
660 (char *)s
->uncompressed_chunk
,
662 (512 * s
->sectorcounts
[chunk
]));
667 case UDRW
: /* copy */
668 ret
= bdrv_pread(bs
->file
, s
->offsets
[chunk
],
669 s
->uncompressed_chunk
, s
->lengths
[chunk
]);
670 if (ret
!= s
->lengths
[chunk
]) {
674 case UDIG
: /* zero */
675 /* see dmg_read, it is treated specially. No buffer needs to be
676 * pre-filled, the zeroes can be set directly. */
679 s
->current_chunk
= chunk
;
684 static int coroutine_fn
685 dmg_co_preadv(BlockDriverState
*bs
, uint64_t offset
, uint64_t bytes
,
686 QEMUIOVector
*qiov
, int flags
)
688 BDRVDMGState
*s
= bs
->opaque
;
689 uint64_t sector_num
= offset
>> BDRV_SECTOR_BITS
;
690 int nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
693 assert((offset
& (BDRV_SECTOR_SIZE
- 1)) == 0);
694 assert((bytes
& (BDRV_SECTOR_SIZE
- 1)) == 0);
696 qemu_co_mutex_lock(&s
->lock
);
698 for (i
= 0; i
< nb_sectors
; i
++) {
699 uint32_t sector_offset_in_chunk
;
702 if (dmg_read_chunk(bs
, sector_num
+ i
) != 0) {
706 /* Special case: current chunk is all zeroes. Do not perform a memcpy as
707 * s->uncompressed_chunk may be too small to cover the large all-zeroes
708 * section. dmg_read_chunk is called to find s->current_chunk */
709 if (s
->types
[s
->current_chunk
] == 2) { /* all zeroes block entry */
710 qemu_iovec_memset(qiov
, i
* 512, 0, 512);
713 sector_offset_in_chunk
= sector_num
+ i
- s
->sectors
[s
->current_chunk
];
714 data
= s
->uncompressed_chunk
+ sector_offset_in_chunk
* 512;
715 qemu_iovec_from_buf(qiov
, i
* 512, data
, 512);
720 qemu_co_mutex_unlock(&s
->lock
);
724 static void dmg_close(BlockDriverState
*bs
)
726 BDRVDMGState
*s
= bs
->opaque
;
732 g_free(s
->sectorcounts
);
733 qemu_vfree(s
->compressed_chunk
);
734 qemu_vfree(s
->uncompressed_chunk
);
736 inflateEnd(&s
->zstream
);
739 static BlockDriver bdrv_dmg
= {
740 .format_name
= "dmg",
741 .instance_size
= sizeof(BDRVDMGState
),
742 .bdrv_probe
= dmg_probe
,
743 .bdrv_open
= dmg_open
,
744 .bdrv_refresh_limits
= dmg_refresh_limits
,
745 .bdrv_child_perm
= bdrv_format_default_perms
,
746 .bdrv_co_preadv
= dmg_co_preadv
,
747 .bdrv_close
= dmg_close
,
750 static void bdrv_dmg_init(void)
752 bdrv_register(&bdrv_dmg
);
755 block_init(bdrv_dmg_init
);